The first month's enrollment numbers for the president's health care law "are not going to be what we want them to be" when they're released later this month, White House senior adviser Dan Pfeiffer acknowledged Sunday morning on ABC's "This Week."

Pfeiffer said that President Obama is "frustrated" with the failures of, the website set up to allow individuals to purchase insurance plans and receive subsidies, in its first month. The site's dysfunction has made it impossible for Americans to sign up in the numbers needed to ensure the viability of the exchanges.

Nevertheless, Pfeiffer predicted that the site's problems would be fixed by the end of November, as has been promised by Jeffrey Zients, the former businessman and Obama administration official brought in to rescue the project. If they are successful in that, Pfeiffer claimed, the question of getting enough Americans enrolled would be answered — "we're going to be able to get this done," he said.

But Pfeiffer also acknowledged that past White House promises about the exchanges haven't panned out.

Pfeiffer, who had claimed that the site would be up and working by Oct. 1, its initial online date, said that "we did believe that. ... These results do not match up to [Obama's] expectations or the American people's expectations. It's inexcusable."

Pfeiffer cited Zient's experience and the addition of a team of "technological experts from Silicon Valley and elsewhere" to the project in predicting that the site would function properly by the end of the month.

Host George Stephanopoulos asked asked Pfeiffer about the president's promise to Americans that, under his health care law, if they like their insurance plan they could keep it. Stephanopoulos referenced a recent Wall Street Journal article reporting that White House aides had debated whether to use that talking point, knowing it would prove hard to defend later on.

"That is not my recollection at all of that," Pfeiffer said of the internal debate.

Pressed by Stephanopoulos on why the president didn't warn that some Americans would lose their health insurance under the law, Pfeiffer denied the Wall Street Journal's account, saying "look, I can't go back in time on this. And I — like I said, I don't recall that — this debate the Wall Street Journal talks about in any way, shape or form."

And Pfeiffer stuck to the original promise, saying that "if you had a plan before the Affordable Care Act passed, it hasn't been changed or canceled, you can keep it."

The same Wall Street Journal piece reported that up to 10 million Americans are expected to lose their insurance by the end of the year.

Many of the cancellations were made because the existing plans did not comply with rules written by the administration after the passage of the president's health care law in 2010.